<template>
  <div id="app">
    <div>
      <span>全选:</span>
      <input type="checkbox" v-model="aa" />
      <button @click="add">反选</button>
      <ul>
        <li v-for="(item, index) in arr" :key="index">
          <input type="checkbox" v-model="item.checked" />
          <span>{{ item.name }}</span>
        </li>
      </ul>
    </div>
  </div>
</template>

<script>
export default {
  data: function () {
    return {
      arr: [
        {
          name: '猪八戒',
          checked: false
        },
        {
          name: '孙悟空',
          checked: false
        },
        {
          name: '唐僧',
          checked: false
        },
        {
          name: '白龙马',
          checked: false
        }
      ]
    }
  },
  computed: {
    aa: {
      get() {
        return this.arr.every(item => item.checked === true)
      },
      set(val) {
        console.log(val)
        this.arr.forEach(item => {
          item.checked = val
        })
      }
    }
  },
  methods: {
    add() {
      this.aa = !this.aa
    }
  }
}
</script>
